General morphology and organelle microtopography in prepubertal ovine cumulus-oocyte-complexes (COCs) at sampling (IVM: 0 hours). a) Representative LM image showing the eccentric or more central profile (inset to Figure1a) of the nucleus (N). Many layers of compact cumulus cells (CCs) adhere to a round zona pellucida (ZP). The ooplasm is rich of vacuoles (in white), lipid droplets (in grey) and organelles (in violet). Bar: 25 μm; inset bar: 20 μm. b)Representative TEM micrograph showing the oocyte and cumulus cells ultrastructure. Compact CCs establish connection to the oocytes by trans-zonal projection (arrows). Mitochondria (m), are interspersed to electron-negative vacuoles (Va), electron-dense lipid droplets (LD). Bar: 5 μm.